Flush joint pipe

Abstract

A pipe has a tubular body with a male end and a female end. The male end has an external surface with a first engagement groove. The female end has an internal surface with a second engagement groove, and an aperture extending from an outer surface of the tubular body to the second engagement groove. The female end receives the male end of another pipe such that the first engagement groove of the male end axially aligns with the second engagement groove of the female end to establish a spline engagement groove having a groove length, L G . A flexible spline is located in the spline engagement groove to lock the pipes together and establish a pipe assembly. The flexible spline has a spline length, L S , and L S ≦L G .

What is claimed is: 
     
         1 . A method of installing pipe in a subterranean location, the method comprising:
 moving a first polymeric pipe segment into a bore in a subterranean location, wherein the bore includes an inner wall at least partially comprising subterranean material;   coupling a second polymeric pipe segment to the first polymeric pipe segment using a flexible spline, wherein the coupled first and second polymeric pipe segments have a diameter that is substantially uniform along an axial length thereof; each of the first and second polymeric pipe segments comprises:
 a pipe having a male end and a female end, the male end comprises a first engagement groove and the female end comprises a second engagement groove, an aperture extending to the second engagement groove, the female end of a first pipe receives the male end of a second pipe such that the first engagement groove of the male end of the second pipe aligns with the second engagement groove of the female end of the first pipe to establish a spline engagement groove having a groove length L G ; and 
 the flexible spline fits through the aperture into the spline engagement groove to prevent the male end of the second pipe from withdrawing from the female end of the first pipe to establish a pipe joint assembly; and the method further comprises: 
   moving the pipe joint assembly into the subterranean location.   
     
     
         2 . The method of  claim 1 , wherein the pipe joint assembly comprises a cross-sectional shape that is substantially uniform along the length thereof. 
     
     
         3 . The method of  claim 1 , wherein the first and second polymeric pipe segments of the pipe joint assembly have an interference fit therebetween. 
     
     
         4 . The method of  claim 1 , wherein each pipe segment comprises an average outside diameter, OD A  that is about ±0.5%, and there is no axial gap between the first and second polymeric pipe segments in the pipe joint assembly. 
     
     
         5 . The method of  claim 4 , wherein the OD A  is about ±0.2%. 
     
     
         6 . The method of  claim 1 , wherein each pipe segment comprises a diameter ratio (DR) that is >7, and a compressive force is required to axially align the first and second engagement grooves because of an interference fit between the pipe segments. 
     
     
         7 . The method of  claim 1 , wherein each pipe segment comprises a diameter ratio (DR) that is DR≦32. 
     
     
         8 . The method of  claim 1 , wherein each pipe segment comprises an impact strength, S, at 23° C.≧284 J (210 ft·lbs). 
     
     
         9 . The method of  claim 1 , wherein each pipe segment comprises an impact strength, S, at 23° C.≦2000 J (1475 ft·lbs). 
     
     
         10 . The method of  claim 1 , wherein the flexible spline has a spline length L S , and L S ≦L G , such that the spline is shorter than the groove length 
     
     
         11 . The method of  claim 10 , wherein L S ≦95% L G . 
     
     
         12 . The method of  claim 10 , wherein L S ≧50% L G . 
     
     
         13 . The method of  claim 1 , wherein the pipe comprises a concentricity relative to a pipe axis, wherein the concentricity at an outside diameter, an inside diameter and an interface between pipe segments is about ±0.5%. 
     
     
         14 . The method of  claim 1 , wherein the pipe joint assembly comprises a flush joint having a tolerance of +/−0.100 inches. 
     
     
         15 . The method of  claim 1 , further comprising:
 locating and exposing a previously installed pipeline in the bore;   pulling a cutting head through the previously installed pipeline;   breaking the previously installed pipeline with the cutting head and expanding the bore to a larger size by pushing pipe fragments of the previously installed pipeline into soil surrounding the bore.   
     
     
         16 . The method of  claim 15 , wherein the cutting head is static. 
     
     
         17 . The method of  claim 15 , wherein the cutting head is dynamic, and comprises at least one of hammering and turning cutters, and a pneumatic system. 
     
     
         18 . The method of  claim 15 , wherein coupling the polymeric pipe segments to each other forms a flush joint; and
 pulling the flush joint into the enlarged bore behind the cutting head.   
     
     
         19 . The method of  claim 18 , wherein the flush joint has a tolerance of +/−0.100 inches.